/*
* This creates a new process as a copy of the old one,
* but does not actually start it yet.
*
* It copies the registers, and all the appropriate
* parts of the process environment (as per the clone
* flags). The actual kick-off is left to the caller.
*/
static __latent_entropy struct task_struct *copy_process(
unsigned long clone_flags,
unsigned long stack_start,
unsigned long stack_size,
int __user *child_tidptr,
struct pid *pid,
int trace,
unsigned long tls,
int node)
{
int retval;
struct task_struct *p;
struct multiprocess_signals delayed;
/*检查参数clone_flags所传递的一致性.
如果
1.CLONE_NEWNS和CLONE_FS都被设。
2.CLONE_THREAD被置位，但是CLONE_SIGHAND标志被清0
（也就是说同一线程组的轻量级进程必须共享信号）
3.CLONE_SIGHAND标志被设置，但CLONE_VM被清0
（也就是要求共享信//号处理程序的轻量级进程必须共享内存描述符）。
以上的三种情况会返回错误代码
int clone(int (*fn)(void *), void *child_stack, int flags, void *arg);
这里fn是函数指针，我们知道进程的4要素，这个就是指向程序的指针，就是所谓的“剧本",
child_stack明显是为子进程分配系统堆栈空间（在linux下系统堆栈空间是2页面，就是8K的内存，
其中在这块内存中，低地址上放入了值，这个值就是进程控制块task_struct的值）,
flags就是标志用来描述你需要从父进程继承那些资源， arg就是传给子进程的参数）。下面是flags可以取的值：
CLONE_PARENT 创建的子进程的父进程是调用者的父进程，新进程与创建它的进程成了“兄弟”而不是“父子”
CLONE_FS 子进程与父进程共享相同的文件系统，包括root、当前目录、umask
CLONE_FILES 子进程与父进程共享相同的文件描述符（file descriptor）表
CLONE_NEWNS 在新的namespace启动子进程，namespace描述了进程的文件hierarchy(等级制度)
CLONE_SIGHAND 子进程与父进程共享相同的信号处理（signal handler）表
CLONE_PTRACE 若父进程被trace，子进程也被trace
CLONE_VFORK 父进程被挂起，直至子进程释放虚拟内存资源
CLONE_VM 子进程与父进程运行于相同的内存空间
CLONE_PID 子进程在创建时PID与父进程一致
CLONE_THREAD Linux 2.4中增加以支持POSIX线程标准，子进程与父进程共享相同的线程群
*/
/*
* Don't allow sharing the root directory with processes in a different
* namespace
*/
/* CLONE_FS 不能与 CLONE_NEWNS 或 CLONE_NEWUSER 同时设置 */
if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
return ERR_PTR(-EINVAL);
if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
return ERR_PTR(-EINVAL);
/*
* Thread groups must share signals as well, and detached threads
* can only be started up within the thread group.
*/
/* 创建线程时线程之间要共享信号处理函数 */
if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
return ERR_PTR(-EINVAL);
/*
* Shared signal handlers imply shared VM. By way of the above,
* thread groups also imply shared VM. Blocking this case allows
* for various simplifications in other code.
*/
/*
* 父子进程共享信号处理函数时必须共享内存地址空间
* 这就是为什么书上写的fork出来的父子进程有其独立的信号处理函数，因为他们的内存地址空间不同
*/
if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
return ERR_PTR(-EINVAL);
/*
* Siblings of global init remain as zombies on exit since they are
* not reaped by their parent (swapper). To solve this and to avoid
* multi-rooted process trees, prevent global and container-inits
* from creating siblings.
*/
/*
* 防止参数init进程的兄弟进程
* 只有init进程的 signal->flags & SIGNAL_UNKILLABLE 为真
* 因为当进程退出时实际上是成为了僵尸进程(zombie),而要通过init进程将它回收，而如果此进程为init的兄弟进程，则没办法将其回收
*/
if ((clone_flags & CLONE_PARENT) &&
current->signal->flags & SIGNAL_UNKILLABLE)
return ERR_PTR(-EINVAL);
/*
* If the new process will be in a different pid or user namespace
* do not allow it to share a thread group with the forking task.
*/
/* 如果新的进程将会有新的用户空间或者pid，则不能让它共享父进程的线程组或者信号处理或者父进程 */
if (clone_flags & CLONE_THREAD) {
if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) ||
(task_active_pid_ns(current) !=
current->nsproxy->pid_ns_for_children))
return ERR_PTR(-EINVAL);
}
/* 附加安全检查 */
/*
* Force any signals received before this point to be delivered
* before the fork happens. Collect up signals sent to multiple
* processes that happen during the fork and delay them so that
* they appear to happen after the fork.
*/
sigemptyset(&delayed.signal);
INIT_HLIST_NODE(&delayed.node);
spin_lock_irq(¤t->sighand->siglock);
if (!(clone_flags & CLONE_THREAD))
hlist_add_head(&delayed.node, ¤t->signal->multiprocess);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
retval = -ERESTARTNOINTR;
if (signal_pending(current))
goto fork_out;
/* 为新进程分配struct task_struct内存和内核栈内存 */
retval = -ENOMEM;
p = dup_task_struct(current, node);
if (!p)
goto fork_out;
/*
* This _must_ happen before we call free_task(), i.e. before we jump
* to any of the bad_fork_* labels. This is to avoid freeing
* p->set_child_tid which is (ab)used as a kthread's data pointer for
* kernel threads (PF_KTHREAD).
*/
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
/*
* Clear TID on mm_release()?
*/
p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr : NULL;
/* ftrace是用于内核性能分析和跟踪的 */
ftrace_graph_init_task(p);
/* mutex初始化，其用于SYSTEM V IPC,具体可见 http://blog.chinaunix.net/uid-7295895-id-3011238.html */
rt_mutex_init_task(p);
#ifdef CONFIG_PROVE_LOCKING
DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
retval = -EAGAIN;
/* 检查 tsk->signal->rlim[RLIMIT_NPROC].rlim_cur是否小于等于用户所拥有的进程数，rlim结构体表示相关资源的最大值 */
if (atomic_read(&p->real_cred->user->processes) >=
task_rlimit(p, RLIMIT_NPROC)) {
/* INIT_USER是root权限。检查父进程是否有root权限 */
if (p->real_cred->user != INIT_USER &&
!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
goto bad_fork_free;
}
current->flags &= ~PF_NPROC_EXCEEDED;
/* 将父进程的cred复制到子进程的real_cred和cred。struct cred用于安全操作的结构 */
retval = copy_creds(p, clone_flags);
if (retval < 0)
goto bad_fork_free;
/*
* If multiple threads are within copy_process(), then this check
* triggers too late. This doesn't hurt, the check is only there
* to stop root fork bombs.
*/
/*
* 进程数量是否超出系统允许最大进程数量，最大进程数量跟内存有关，
* 一般原则是所有的进程内核栈(默认8K)加起来不超过总内存的1/8，
* 可通过/proc/sys/kernel/threads-max改写此值
*/
retval = -EAGAIN;
if (nr_threads >= max_threads)
goto bad_fork_cleanup_count;
delayacct_tsk_init(p); /* Must remain after dup_task_struct() */
/* 清除 PF_SUPERPRIV(表示进程使用了超级用户权限) 和 PF_WQ_WORKER(使用了工作队列) */
p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE);
/* 设置 PF_FORKNOEXEC 表明此子进程还没有进行 execve() 系统调用 */
p->flags |= PF_FORKNOEXEC;
/* 初始化子进程的子进程链表和兄弟进程链表为空 */
INIT_LIST_HEAD(&p->children);
INIT_LIST_HEAD(&p->sibling);
/* 见 http://www.ibm.com/developerworks/cn/linux/l-rcu/ */
rcu_copy_process(p);
p->vfork_done = NULL;
/* 初始化分配锁，此锁用于保护分配内存，文件，文件系统等操作 */
spin_lock_init(&p->alloc_lock);
/* 信号列表初始化，此列表保存被挂起的信号 */
init_sigpending(&p->pending);
/* 代码执行时间变量都置为0 */
p->utime = p->stime = p->gtime = 0;
#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
p->utimescaled = p->stimescaled = 0;
#endif
prev_cputime_init(&p->prev_cputime);
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
seqcount_init(&p->vtime.seqcount);
p->vtime.starttime = 0;
p->vtime.state = VTIME_INACTIVE;
#endif
#if defined(SPLIT_RSS_COUNTING)
memset(&p->rss_stat, 0, sizeof(p->rss_stat));
#endif
/* 此变量一般用于epoll和select，从父进程复制过来 */
p->default_timer_slack_ns = current->timer_slack_ns;
/* 初始化进程IO计数结构 */
task_io_accounting_init(&p->ioac);
acct_clear_integrals(p);
/* 初始化cputime_expires结构 */
posix_cpu_timers_init(p);
/* 设置进程创建时间 */
p->start_time = ktime_get_ns();
p->real_start_time = ktime_get_boot_ns();
/* io_context 和 audit_context 置空 */
p->io_context = NULL;
audit_set_context(p, NULL);
/*
* cgroup和namespace类似，也是将进程进行分组，但它的目的和namespace不一样，
* namespace是为了隔离进程组之间的资源，而cgroup是为了对一组进程进行统一的资源监控和限制。
*/
cgroup_fork(p);
#ifdef CONFIG_NUMA
p->mempolicy = mpol_dup(p->mempolicy);
if (IS_ERR(p->mempolicy)) {
retval = PTR_ERR(p->mempolicy);
p->mempolicy = NULL;
goto bad_fork_cleanup_threadgroup_lock;
}
#endif
#ifdef CONFIG_CPUSETS
p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
p->cpuset_slab_spread_rotor = NUMA_NO_NODE;
seqcount_init(&p->mems_allowed_seq);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
p->irq_events = 0;
p->hardirqs_enabled = 0;
p->hardirq_enable_ip = 0;
p->hardirq_enable_event = 0;
p->hardirq_disable_ip = _THIS_IP_;
p->hardirq_disable_event = 0;
p->softirqs_enabled = 1;
p->softirq_enable_ip = _THIS_IP_;
p->softirq_enable_event = 0;
p->softirq_disable_ip = 0;
p->softirq_disable_event = 0;
p->hardirq_context = 0;
p->softirq_context = 0;
#endif
p->pagefault_disabled = 0;
#ifdef CONFIG_LOCKDEP
p->lockdep_depth = 0; /* no locks held yet */
p->curr_chain_key = 0;
p->lockdep_recursion = 0;
lockdep_init_task(p);
#endif
#ifdef CONFIG_DEBUG_MUTEXES
p->blocked_on = NULL; /* not blocked yet */
#endif
#ifdef CONFIG_BCACHE
p->sequential_io = 0;
p->sequential_io_avg = 0;
#endif
/* 初始化子进程的调度优先级和策略，在此并没有将此进程加入到运行队列，在copy_process返回之后加入 */
/* Perform scheduler related setup. Assign this task to a CPU. */
retval = sched_fork(clone_flags, p);
if (retval)
goto bad_fork_cleanup_policy;
/* perf event是一个性能调优工具，具体见 http://blog.sina.com.cn/s/blog_98822316010122ex.html */
retval = perf_event_init_task(p);
if (retval)
goto bad_fork_cleanup_policy;
retval = audit_alloc(p);
if (retval)
goto bad_fork_cleanup_perf;
/* copy all the process information */
/* 初始化 p->sysvshm.shm_clist 链表头 */
shm_init_task(p);
retval = security_task_alloc(p, clone_flags);
if (retval)
goto bad_fork_cleanup_audit;
/* copy_semundo, copy_files, copy_fs, copy_sighand, copy_signal, copy_mm, copy_namespaces, copy_io
* 都是根据clone_flags从父进程做相应的复制
* */
retval = copy_semundo(clone_flags, p);
if (retval)
goto bad_fork_cleanup_security;
retval = copy_files(clone_flags, p);
if (retval)
goto bad_fork_cleanup_semundo;
retval = copy_fs(clone_flags, p);
if (retval)
goto bad_fork_cleanup_files;
retval = copy_sighand(clone_flags, p);
if (retval)
goto bad_fork_cleanup_fs;
/* 如果创建的是线程，直接返回0，如果创建的是进程，则会将父进程的信号屏蔽和安排复制到子进程中 */
retval = copy_signal(clone_flags, p);
if (retval)
goto bad_fork_cleanup_sighand;
/*
* 如果是进程，则将父进程的mm_struct结构复制到子进程中，然后修改当中属于子进程有别于父进程的信息(如页目录)
* 如果是线程，则将子线程的mm指针和active_mm指针都指向父进程的mm指针所指结构。
*/
retval = copy_mm(clone_flags, p);
if (retval)
goto bad_fork_cleanup_signal;
retval = copy_namespaces(clone_flags, p);
if (retval)
goto bad_fork_cleanup_mm;
retval = copy_io(clone_flags, p);
if (retval)
goto bad_fork_cleanup_namespaces;
/*
* 初始化子进程内核栈和thread_struct结构体
* 当进程切换时，进程的硬件上下文一般保存于三个地方: tss_struct(保存进程内核栈地址，I/O许可权限位)，thread_struct(大部分非通用寄存器)，进程内核栈(通用寄存器)
* copy_thread函数会将父进程的thread_struct和内核栈数据复制到子进程中，并将子进程的返回值置为0(x86返回值保存在eax中，arm保存在r0中，即把eax或者r0所在的内核栈数据置为0)
* copy_thread函数还会将子进程的eip寄存器值设置为ret_from_fork()的地址，即当子进程首次被调用就立即执行系统调用clone返回。
* 所以应用层调用fork()函数后，子进程返回0，父进程返回子进程ID(返回子进程ID在之后代码中会实现)
*/
retval = copy_thread_tls(clone_flags, stack_start, stack_size, p, tls);
if (retval)
goto bad_fork_cleanup_io;
/* 判断是不是init进程 */
if (pid != &init_struct_pid) {
pid = alloc_pid(p->nsproxy->pid_ns_for_children);/* 分配pid */
if (IS_ERR(pid)) {
retval = PTR_ERR(pid);
goto bad_fork_cleanup_thread;
}
}
#ifdef CONFIG_BLOCK
p->plug = NULL;
#endif
#ifdef CONFIG_FUTEX
p->robust_list = NULL;
#ifdef CONFIG_COMPAT
p->compat_robust_list = NULL;
#endif
INIT_LIST_HEAD(&p->pi_state_list);
p->pi_state_cache = NULL;
#endif
/*
* sigaltstack should be cleared when sharing the same VM
*/
/*
* 如果共享VM或者vfork创建，信号栈清空
*/
if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
sas_ss_reset(p);
/*
* Syscall tracing and stepping should be turned off in the
* child regardless of CLONE_PTRACE.
*/
/*
* 系统调用跟踪时应该禁止单步执行
*/
user_disable_single_step(p);
clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
#ifdef TIF_SYSCALL_EMU
clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
#endif
clear_all_latency_tracing(p);
/* ok, now we should be set up.. */
/* 将子进程的PID设置为分配的PID在全局namespace中分配的值，在不同namespace中进程的PID不同，而p->pid保存的是全局的namespace中所分配的PID */
p->pid = pid_nr(pid);
if (clone_flags & CLONE_THREAD) {/* 创建的是线程 */
p->exit_signal = -1;
p->group_leader = current->group_leader;/* 线程组的所有线程的group_leader都一致 */
p->tgid = current->tgid;/* 线程组的所有线程的tgid都一致，使用getpid返回的就是tgid */
} else {
/* 创建的是子进程 */
if (clone_flags & CLONE_PARENT)
p->exit_signal = current->group_leader->exit_signal;
else
p->exit_signal = (clone_flags & CSIGNAL);
p->group_leader = p;
p->tgid = p->pid;/* tgid与pid一致，所以当创建子线程时，tgid与主线程的一致 */
}
p->nr_dirtied = 0;/* 初始化页框中脏页数量为0 */
p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);/* 初始化脏页数量临界值，当脏页数量到达临界值时，会调用balance_dirty_pages()将脏页写入磁盘 */
p->dirty_paused_when = 0;/* 将脏页写入磁盘的开始时间 */
p->pdeath_signal = 0;
INIT_LIST_HEAD(&p->thread_group);/* 初始化线程组链表为空 */
p->task_works = NULL;
cgroup_threadgroup_change_begin(current);
/*
* Ensure that the cgroup subsystem policies allow the new process to be
* forked. It should be noted the the new process's css_set can be changed
* between here and cgroup_post_fork() if an organisation operation is in
* progress.
*/
retval = cgroup_can_fork(p);
if (retval)
goto bad_fork_free_pid;
/*
* Make it visible to the rest of the system, but dont wake it up yet.
* Need tasklist lock for parent etc handling!
*/
/* 到此系统中已经存在此进程(线程)，但是它还不能够执行，需要等待父进程对其处理，这里会上锁 */
write_lock_irq(&tasklist_lock);
/* CLONE_PARENT re-uses the old parent */
if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
/* 创建的是兄弟进程或者相同线程组线程 */
/* 其父进程为父进程的父进程 */
p->real_parent = current->real_parent;
/* 其父进程执行域为父进程的父进程执行域 */
p->parent_exec_id = current->parent_exec_id;
} else {
/* 创建的是子进程 */
/* 父进程为父进程 */
p->real_parent = current;
/* 父进程的执行域为父进程的执行域 */
p->parent_exec_id = current->self_exec_id;
}
klp_copy_process(p);
/* 当前进程信号处理上锁，这里应该是禁止了信号处理 */
spin_lock(¤t->sighand->siglock);
/*
* Copy seccomp details explicitly here, in case they were changed
* before holding sighand lock.
*/
/*
* seccomp与系统安全有关，具体见 http://note.sdo.com/u/634687868481358385/NoteContent/M5cEN~kkf9BFnM4og00239
*/
copy_seccomp(p);
/*
* 在fork之前，进程组和会话信号都需要送到父亲结点，而在fork之后，这些信号需要送到父亲和孩子结点。
* 如果我们在将新进程添加到进程组的过程中出现一个信号，而这个挂起信号会导致当前进程退出(current)，我们的子进程就不能够被kill或者退出了
* 所以这里要检测父进程有没有信号被挂起。
*/
rseq_fork(p, clone_flags);
/* Don't start children in a dying pid namespace */
if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) {
retval = -ENOMEM;
goto bad_fork_cancel_cgroup;
}
/* Let kill terminate clone/fork in the middle */
if (fatal_signal_pending(current)) {
retval = -EINTR;
goto bad_fork_cancel_cgroup;
}
init_task_pid_links(p);
if (likely(p->pid)) {
/* 如果子进程需要跟踪，就将 current->parent 赋值给 tsk->parent ，并将子进程插入调试程序的跟踪链表中 */
ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
init_task_pid(p, PIDTYPE_PID, pid);
/* 如果是子进程(其实就是判断 p->exit_signal 是否大于等于0，创建的是线程的话，exit_signal的值为-1) */
if (thread_group_leader(p)) {
/* p->pids[PIDTYPE_PGID].pid = current->group_leader->pids[PIDTYPE_PGID].pid; PGID为进程组ID，所以直接复制父进程的pgid */
init_task_pid(p, PIDTYPE_TGID, pid);
/* p->pids[PIDTYPE_SID].pid = current->group_leader->pids[PIDTYPE_SID].pid; SID为会话组ID，当没有使用setsid()时，子进程的sid与父进程一致 */
init_task_pid(p, PIDTYPE_PGID, task_pgrp(current));
init_task_pid(p, PIDTYPE_SID, task_session(current));
/* return pid->numbers[pid->level].nr == 1; 判断新进程是否处于一个新创建的namespace中(新进程所在的新namespace中的pid会为1，以此判断) */
if (is_child_reaper(pid)) {
/* 将当前namespace的init进程设置为此新进程 */
ns_of_pid(pid)->child_reaper = p;
p->signal->flags |= SIGNAL_UNKILLABLE;
}
p->signal->shared_pending.signal = delayed.signal;
p->signal->tty = tty_kref_get(current->signal->tty);
/*
* Inherit has_child_subreaper flag under the same
* tasklist_lock with adding child to the process tree
* for propagate_has_child_subreaper optimization.
*/
p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper ||
p->real_parent->signal->is_child_subreaper;
/* 将此进程添加到父进程的子进程链表 */
list_add_tail(&p->sibling, &p->real_parent->children);
/* 将此进程task_struct加入到task链表中 */
list_add_tail_rcu(&p->tasks, &init_task.tasks);
/* 将新进程描述符的pgid结构插入pgid_hash */
attach_pid(p, PIDTYPE_TGID);
/* 将新进程描述符的sid结构插入sid_hash */
attach_pid(p, PIDTYPE_PGID);
attach_pid(p, PIDTYPE_SID);
/* 当前cpu进程数量加1 */
__this_cpu_inc(process_counts);
} else {
/* 创建的是线程，这里的处理导致了线程会共享信号 */
current->signal->nr_threads++;
atomic_inc(¤t->signal->live);
atomic_inc(¤t->signal->sigcnt);
task_join_group_stop(p);
/* 将新线程的thread_group结点加入到线程组的领头线程的thread_group链表中 */
list_add_tail_rcu(&p->thread_group,
&p->group_leader->thread_group);
/* 将新线程的thread_node结点加入的新线程的signal->thread_head中 */
list_add_tail_rcu(&p->thread_node,
&p->signal->thread_head);
}
/* 将新进程描述符的pid结构插入pid_hash */
attach_pid(p, PIDTYPE_PID);
nr_threads++;/* 当前系统进程数加1 */
}
total_forks++;/* 已创建的进程数量加1 */
hlist_del_init(&delayed.node);
spin_unlock(¤t->sighand->siglock);/* 释放当前进程信号处理锁 */
syscall_tracepoint_update(p);
write_unlock_irq(&tasklist_lock);/* 释放tasklist_lock锁 */
proc_fork_connector(p);/* 将新进程与proc文件系统进行关联 */
cgroup_post_fork(p);
cgroup_threadgroup_change_end(current);/* 如果创建的是线程，释放此锁 */
perf_event_fork(p);
trace_task_newtask(p, clone_flags);
uprobe_copy_process(p, clone_flags);
/* 返回新进程的task_struct结构 */
return p;
bad_fork_cancel_cgroup:
spin_unlock(¤t->sighand->siglock);
write_unlock_irq(&tasklist_lock);
cgroup_cancel_fork(p);
bad_fork_free_pid:
cgroup_threadgroup_change_end(current);
if (pid != &init_struct_pid)
free_pid(pid);
bad_fork_cleanup_thread:
exit_thread(p);
bad_fork_cleanup_io:
if (p->io_context)
exit_io_context(p);
bad_fork_cleanup_namespaces:
exit_task_namespaces(p);
bad_fork_cleanup_mm:
if (p->mm)
mmput(p->mm);
bad_fork_cleanup_signal:
if (!(clone_flags & CLONE_THREAD))
free_signal_struct(p->signal);
bad_fork_cleanup_sighand:
__cleanup_sighand(p->sighand);
bad_fork_cleanup_fs:
exit_fs(p); /* blocking */
bad_fork_cleanup_files:
exit_files(p); /* blocking */
bad_fork_cleanup_semundo:
exit_sem(p);
bad_fork_cleanup_security:
security_task_free(p);
bad_fork_cleanup_audit:
audit_free(p);
bad_fork_cleanup_perf:
perf_event_free_task(p);
bad_fork_cleanup_policy:
lockdep_free_task(p);
#ifdef CONFIG_NUMA
mpol_put(p->mempolicy);
bad_fork_cleanup_threadgroup_lock:
#endif
delayacct_tsk_free(p);
bad_fork_cleanup_count:
atomic_dec(&p->cred->user->processes);
exit_creds(p);
bad_fork_free:
p->state = TASK_DEAD;
put_task_stack(p);
free_task(p);
fork_out:
spin_lock_irq(¤t->sighand->siglock);
hlist_del_init(&delayed.node);
spin_unlock_irq(¤t->sighand->siglock);
return ERR_PTR(retval);
}
